Ethylene-alpha-olefin copolymer

ABSTRACT

An ethylene-α-olefin copolymer which is a copolymer of ethylene with a C 3-20  α-olefin and which satisfies the following conditions (a) to (c):  
     (a) the density (D) is from 0.850 to 0.950 g/cm 3 ,  
     (b) the relation between the melt tension (MT) and the melt flow rate (MFR) at 190° C. satisfies the following formula (1):  
     log(MT)≧−0.91×log(MFR)+0.06   (1),  
     and  
     (c) the following three formulae (2), (3) and (4) are satisfied:  
     Tmax≦972D−813   (2)  
     logW 60 ≦−0.114 Tmax+9.48   (3)  
     logW 90 ≧0.0394 Tmax−2.95   (4)  
     where D is the density, Tmax is the elution peak temperature (° C.) by the cross fractionation measurement, W 60  is the weight ratio (wt %) of a soluble content at 60° C. or lower, and W 90  is the weight ratio (wt %) of a soluble content at 90° C. or higher.

[0001] The present invention relates to an ethylene-α-olefin copolymer.More particularly, the present invention relates to an ethylene-α-olefincopolymer, of which the MFR, the MT, the density and the elutionbehavior in cross fractionation satisfy certain specific relationalformulae. When the copolymer of the present invention is molded into afilm, it is excellent in the molding stability, and it is possible toobtain a film which is excellent in transparency, gloss and drape andfree from stickiness.

[0002] A copolymer of ethylene with an α-olefin has been used in a largeamount for various uses, particularly for bags, since a film obtained byblown-film extrusion of such a copolymer is excellent in mechanicalproperties such as tensile strength and impact strength. However, a filmobtainable by blown-film extrusion of a copolymer of ethylene with anα-olefin alone has had a problem that the transparency is inadequate inmany uses.

[0003] On the other hand, an ethylene-α-olefin copolymer produced bymeans of a metallocene catalyst has been proposed in recent years. Thetransparency of this copolymer is improved over the conventionalethylene-α-olefin copolymer but is still inadequate, and its molecularweight distribution is so narrow that the babble stability duringmolding is not good (JP-A-4-213309).

[0004] Under the circumstances, there has been a proposal to improve themolding characteristic of polyethylene by broadening the molecularweight distribution by a method of carrying out polymerization inmultisteps (JP-A-3-23717) or carrying out polymerization by using two ormore metallocene compounds in combination (JP-A-5-155932 andJP-A-60-35006), or a proposal of a method wherein a polyethyleneprepared by a high pressure method is mixed to an ethylene-α-olefincopolymer produced by means of a metallocene catalyst.

[0005] Further, International Patent Application WO93/08221 discloses aresin which is described to be excellent in the fluidity in spite of itsnarrow molecular weight distribution. However, even the resin disclosedin this application has had no adequate transparency, although it isbetter in fluidity and moldability to some extent than the formerproposals.

[0006] Accordingly, it has been desired to develop an ethylene-α-olefincopolymer which, when formed into a film, provides adequate transparencywithout impairing excellent mechanical properties and processabilityspecific to an ethylene-α-olefin copolymer.

[0007] The present inventors have conducted various studies to solve theabove problems and as a result, have found that such problems can besolved by an ethylene-α-olefin copolymer, of which the melt tension andthe melt flow rate have a certain specific relation, and which satisfiesa certain specific elution condition. The present invention has beenaccomplished on the basis of this discovery.

[0008] That is, the present invention provides an ethylene-α-olefincopolymer which is a copolymer of ethylene with a C₃₋₂₀ α-olefin andwhich satisfies the following conditions (a) to (c):

[0009] (a) the density (D) is from 0.850 to 0.950 g/cm³,

[0010] (b) the relation between the melt tension (MT) and the melt flowrate (MFR) at 190° C. satisfies the following formula (1):

log(MT)≧−0.91×log(MFR)+0.06   (1),

[0011] and

[0012] (c) the following three formulae (2), (3) and (4) are satisfied:

Tmax≦972D−813   (2)

logW₆₀≦−0.114 Tmax+9.48   (3)

logW₉₀≧0.0394 Tmax−2.95   (4)

[0013] where D is the density, Tmax is the elution peak temperature (°C.) by the cross fractionation measurement, W₆₀ is the weight ratio (wt%) of a soluble content at 60° C. or lower, and W₉₀ is the weight ratio(wt %) of a soluble content at 90° C. or higher.

[0014] Preferred is the ethylene-α-olefin copolymer wherein saidcondition (c) is such that the following formulae are satisfied:

Tmax≦972D−816   (2)′

logW₆₀≦−0.114 Tmax+9.48   (3)

logW₉₀≧0.0394 Tmax−2.81   (4)′

[0015] Particularly preferred is the ethylene-α-olefin copolymer whereinthe density (D) of said condition (a) is from 0.850 to 0.935 g/cm³.

[0016] Now, the present invention will be described in detail withreference to the preferred embodiments.

[0017] The copolymer of the present invention has a density (D) of from0.850 to 0.950 g/cm³, preferably from 0.850 to 0.935 g/cm³ (condition(a)). If the density is too low, the drape of the formed film productwill be inadequate, and the processability by e.g. a bag-manufacturingmachine will be poor, such being undesirable. On the other hand, if itis too high, no adequate transparency of the film will be secured.

[0018] Here, the density is one measured by a density gradient tubemethod after a strand obtained at the time of measuring the melt indexis subjected to heat treatment at 100° C. for one hour and left to coolat room temperature for one hour.

[0019] Further, the copolymer of the present invention is required tosatisfy a condition such that the relation between the melt tension (MT)and the melt flow rate (MFR) at 190° C. satisfies:

log(MT)≧−0.91×log(MFR)+0.06   (1)

[0020] preferably,

log(MT)≧−0.91×log(MFR)+0.12

[0021] more preferably,

log(MT)≧−0.91×log(MFR)+0.21

[0022] (condition (b)). If this relational formula is not satisfied,there will be a problem that during blown-film extrusion, the bubble islikely to be broken or swaying (the stability of the bubble can not bemaintained).

[0023] It is particularly preferred that MFR of the copolymer is from0.1 to 50 g/10 min. If MFR is too low, the fluidity at the time ofmelting tends to be inadequate, and the molded product tends to havesurface roughness. On the other hand, if MFR is too high, the strengthof the molded product tends to deteriorate, such being undesirable.

[0024] Here, MFR is one measured at 190° C. under a load of 2.16 kg inaccordance with ASTMD 1238. The melt tension (MT) was measured by meansof a capirograph manufactured by Kabushiki Kaisha Toyo Seiki Seisakushounder such conditions that the nozzle diameter was 2.095 mmφ, the nozzlelength was 8 mm, the flow-in angle was 180°, the temperature was 190°C., the extrusion rate was 1.0 cm/min, the withdrawing rate was 4.0m/min, and the distance from the die outlet to the lower end of theV-pully of the tension detector, was 40 cm.

[0025] A particularly important point in the present invention is thatthe copolymer has the specific copolymer composition distribution whilehaving a narrow molecular weight. Such a copolymer compositiondistribution is characterized in that the maximum peak temperature(Tmax) in the elution curve by cross fractionation shifts to arelatively low side depending upon the density of the copolymer, and theamount of soluble components in a high temperature region is relativelylarge depending upon Tmax. Namely, in the present invention, the density(D), the temperature (Tmax) at the maximum peak position, the solublecontent weight ratio at 60° C. or lower (W₆₀) and the soluble contentweight ratio at 90° C. or higher (W₉₀) are required to satisfy thefollowing three formulae simultaneously, for example, in order to attainexcellent film-molding stability during blown-film extrusion forexcellent transparency of the resulting film (condition (c)):

Tmax≦972D−813   (2)

logW₆₀≦−0.114 Tmax+9.48   (3)

logW₉₀≧0.0394 Tmax−2.95   (4)

[0026] preferably,

Tmax≦972D−816   (2)′

logW₆₀≦−0.114 Tmax+9.48   (3)

logW₉₀≧0.0394 Tmax−2.81   (4)′

[0027] If the above formulae are not satisfied, the stability of thebubble can not be maintained when such a resin is formed into a film byblown-film extrusion, and the resulting film tends to be poor in thetransparency (haze) and in the drape, and the film surface tends to besticky.

[0028] Here, the measurement by cross fractionation was carried out bymeans of a cross fractionation column (CFC) manufactured by MitsubishiChemical Company Ltd. under such conditions that the solvent waso-dichlorobenzene, the column size was 0.46 mm in diameter×15 cm, thepacking was glass beads (0.1 mm in diameter), the detector was aninfrared detector (MIRAN 1A), the measuring wave number was 3.42 μm, thesample concentration was 3 mg/ml and the injected amount was 0.4 ml.Specifically, a sample solution was introduced into the column at 140°C. under the above conditions, cooled to 0° C. at a temperature loweringrate of 1° C./min and maintained for 30 minutes, and thereafter, it waseluted at each temperature of 26 divisions i.e. 0, 10, 20, 30, 35, 40,45, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 100,120 and 140° C., and the polymer concentrations were detected by aninfrared detector, whereupon an elution curve was obtained. In thesecond and subsequent divisions, the sample solution in the column wasmaintained for 40 minutes at each temperature and then eluted. The flowrate was 1 ml/min.

[0029] Thus, the ethylene-α-olefin copolymer of the present inventionsatisfies the above conditions (a) to (c). Further, in a case where afilm excellent in transparency with a density exceeding 0.9 g/cm³,preferably from 0.900 to 0.934 g/cm, is desired, it is preferred thatthe copolymer satisfies the following condition (d) in addition to theabove conditions (a) to (c):

(d) the film haze (%)≦1.5×10⁴(D−0.9)²+3   (5)

[0030] preferably, the film haze (%)≦1.5×10⁴(D−0.9)²+2

[0031] more preferably, the film haze (%)≦1.0×10⁴(D−0.9)²+2

[0032] Here, the film haze is measured by using a film having athickness of 30 μm formed by blown-film extrusion under a condition of ablow-up ratio of 2.0. D is the density.

[0033] The above described copolymer of the present invention may beobtained by various methods, for example, a method whereinethylene-α-olefin copolymers separately produced by means of so-calledmetallocene catalysts, are blended by kneading, a method whereinpolymerization is carried out in a series of multisteps differing in theset density conditions, or a method wherein two types of metallocenecompounds are used in combination to obtain copolymers having differentdensities. The method is not particularly limited so long as the abovementioned conditions (a) to (c), or (a) to (d), are satisfied. However,preferred is a copolymer obtained by polymerization by means of acatalyst comprising the following components (A) to (C):

[0034] (A) a metallocene-type transition metal compound

[0035] (B) an ion-exchanging layered compound or a non-layered inorganicsilicate, and, if necessary,

[0036] (C) an organic aluminum compound.

[0037] The metallocene-type transition metal compound of component (A),is an organometallic compound or a cation-type complex thereof, composedof (i) one or two cyclopentadienyl-type ligands which may besubstituted, or one or two cyclopentadienyl ring-containing ligandswherein substituents may bond to form a fused ring, and (ii) atransition metal of Group 3, 4, 5 or 6 of the long-form Periodic Table(the Periodic Table employing 18 Group system defined by IUPAC in 1989,and the same applies hereinafter).

[0038] Preferred as such a metallocene-type transition metal compound ofcomponent (A) is a compound of the following formula (1) or (2):

(CpR ⁴ _(a)H_(5-a))_(p)(CpR⁵ _(b)H_(5-b))_(q)MR⁶ _(r)   (1)

[(CpR⁴ _(a)H_(5-a))_(p)(CpR⁵ _(b)H_(5-b))_(q)MR⁶_(r)L_(m)]^(n+)[R⁷]^(n−)  (2)

[0039] wherein CpR⁴ _(a)H_(5-a) and CpR⁵ _(b)H_(5-b) are acyclopentadienyl (Cp) group derivative.

[0040] In the formula (1) or (2), each of R⁴ and R⁵ which may be thesame or different, is a C₁₋₂₀ hydrocarbon group which may besubstituted, a silicon-containing group, a phosphorus-containing group,a nitrogen-containing group or an oxygen-containing group.

[0041] Examples of R⁴ and R⁵ groups include an alkyl group such asmethyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl,isopentyl, hexyl, heptyl, octyl, nonyl or decyl; an aryl group such asphenyl, p-tolyl, o-tolyl or m-tolyl; a halo-substituted hydrocarbongroup such as fluoromethyl, fluoroethyl, fluorophenyl, chloromethyl,chloroethyl, chlorophenyl, bromomethyl, bromoethyl, bromophenyl,iodomethyl, iodoethyl or iodophenyl; a silicon-containing substituentsuch as trimethylsilyl, triethylsilyl or triphenylsilyl; an alkoxy groupsuch as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy ort-butoxy; and an aryloxy group such as phenoxy, methylphenoxy,pentamethylphenoxy, p-tolyloxy, m-tolyloxy or o-tolyloxy. Among them,preferred are a C₁₋₄ alkyl group such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl or t-butyl; a silicon-containing substituentsuch as trimethylsilyl; an alkoxy group such as methoxy; and an aryloxygroup such as phenoxy.

[0042] Further, R⁴ and R⁵ may bond each other to form a crosslinkinggroup.

[0043] Specifically, it may be an alkylene group such as methylene orethylene; an alkylidene group such as ethylidene, propylidene,isopropylidene, phenylmethylidene or diphenylmethylidene; asilicon-containing crosslinking group such as dimethylsilylene,diethylsilylene, dipropylsilylene, diisopropylsilylene,diphenylsilylene, methylethylsilylene, methylphenylsilylene,methylisopropylsilylene or methyl-t-butylsilylene; agermanium-containing crosslinking group such as dimethylgermilene,diethylgermilene, dipropylgermilene, diisopropylgermilene,diphenylgermilene, methylethylgermilene, methylphenylgermilene,methylisopropylgermilene or methyl-t-butylgermilene; an amino group; ora phosphinyl group.

[0044] Still further, R⁴ and R⁴, or R⁵ and R⁵ may respectively bond eachother to form a ring. Preferable examples include an indenyl group, atetrahydroindenyl group, a fluorenyl group and an octahydrofluorenylgroup, which may be substituted.

[0045] Examples of a R⁶ group include a C₁₋₂₀ hydrocarbon group whichmay be substituted, hydrogen, a halogen, a silicon-containingsubstituent, an alkoxy group, an aryloxy group, an amide group or athioalkoxy group. Specific examples include an alkyl group such asmethyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl,isopentyl, hexyl, heptyl, octyl, nonyl or decyl; an aryl group such asphenyl, p-tolyl, o-tolyl or m-tolyl; a halo-substituted hydrocarbongroup such as fluoromethyl, fluoroethyl, fluorophenyl, chloromethyl,chloroethyl, chlorophenyl, bromomethyl, bromoethyl, bromophenyl,iodomethyl, iodoethyl or iodophenyl; a halogen atom such as fluorine,chlorine, bromine or iodine; a silicon-containing substituent such astrimethylsilyl, triethylsilyl or triphenylsilyl; an alkoxy group such asmethoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or t-butoxy; anaryloxy group such as phenoxy, methylphenoxy, pentamethylphenoxy,p-tolyloxy, m-tolyloxy or o-tolyloxy; an amide group such asdimethylamide, diethylamide, dipropylamide, diisopropylamide,ethyl-t-butylamide or bis(trimethylsilyl)amide; and a thioalkoxy groupsuch as methylthioalkoxy, ethylthioalkoxy, propylthioalkoxy,butylthioalkoxy, t-butylthioalkoxy or phenylthioalkoxy. Preferableexamples include hydrogen, a methyl group, an ethyl group, a propylgroup, an isopropyl group, a butyl group, a phenyl group, a halogen atomsuch as chlorine, a methoxy group, an ethoxy group, a propoxy group, anisopropoxy group, a dimethylamide group and a methylthioalkoxy group,and more preferable examples include hydrogen, a methyl group andchlorine.

[0046] Further, R⁶ may bond with R⁴, R⁵ or Cp, and examples of such aligand include CpH₄(CH₂)_(n)O— (1≦n≦5), CpMe₄(CH₂)_(n)O— (1≦n≦5),CpH₄(Me₂Si)(t-Bu)N— and Cp(Me₄(Me₂Si)(t-Bu)N— (Cp is a cyclopentadienylgroup, Me is a methyl group, and Bu is a butyl group).

[0047] Still further, R⁶ may bond each other to form a didentate ligand,examples of which include —OCH₂O—, —OCH₂CH₂O— and —O(o-C₆H₄)O—.

[0048] M is an atom of Group 3, 4, 5 or 6 of the long-form PeriodicTable, examples of which include scandium, yttrium, lanthanum, cerium,praseodymium, neodymium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium, lutetium, actinium,thorium, protactinium, uranium, titanium, zirconium, hafnium, vanadium,niobium, tantalum, chromium, molybdenum and tungsten. Preferableexamples include Group 4 atoms such as titanium, zirconium and hafnium.They may be used in a mixture.

[0049] L is an electrically neutral ligand, and m is its number and isan integer of 0 or more. Examples include ethers such as diethyl ether,tetrahydrofuran or dioxane; nitriles such as acetonitrile; amides suchas dimethylformamide; phosphines such as trimethylphosphine; and aminessuch as trimethylamine. Preferable examples include tetrahydrofuran,trimethylphosphine or trimethylamine.

[0050] [R⁷]^(n−) is one or more anions to neutralize a cation, andexamples include tetraphenyl borate, tetra(p-tolyl)borate, carbadodecaborate, dicarbaundeca borate, tetrakis(pentafluorophenyl)borate,tetrafluoroborate, and hexafluorophosphate. Preferable examples includetetraphenyl borate, tetra(p-tolyl)borate, tetrafluoroborate andhexafluorophosphate. a and b are respectively integers of from 0 to 5.Also, p, q and r are 0 or positive integers which satisfy the equation,p+q+r=V (V=the valence of M), in case that the metallocene-typetransition metal compound is a compound of the formula (1), or p, q andr are 0 or positive integers which satisfy the equation, p+q+r=V−n, incase that the metallocene-type transition metal compound is a compoundof the formula (2). Usually, p and q are integers of from 0 to 3,preferably 0 or 1, and r is an integer of from 0 to 3, preferably 1 or2. n is an integer to satisfy 0≦n≦V.

[0051] The above described catalyst is capable of producing any one ofan isotactic polymer, a syndiotactic polymer and an atactic polymer.

[0052] Taking zirconium as an example, specific examples of the abovemetallocene-type transition metal compound corresponding to the formula(1) include

[0053] bis(methylcyclopentadienyl)zirconium dichloride,

[0054] bis(ethylcyclopentadienyl)zirconium dichloride,

[0055] bis(methylcyclopentadienyl)zirconium dimethyl,

[0056] bis(ethylcyclopentadienyl)zirconium dimethyl,

[0057] bis(methylcyclopentadienyl)zirconium dihydride,

[0058] bis(ethylcyclopentadienyl)zirconium dihydride,

[0059] bis(dimethylcyclopentadienyl)zirconium dichloride,

[0060] bis(trimethylcyclopentadienyl)zirconium dichloride,

[0061] bis(tetramethylcyclopentadienyl)zirconium dichloride,

[0062] bis(ethyltetramethylcyclopentadienyl)zirconium dichloride,bis(ethyl-n-butylcyclopentadienyl)zirconium dichloride,bis(ethylmethylcyclopentadienyl)zirconium

[0063] dichloride, bis(n-butylmethylcyclopentadienyl)zirconiumdichloride, bis(indenyl)zirconium dichloride,

[0064] bis(dimethylcyclopentadienyl)zirconium dimethyl,

[0065] bis(trimethylcyclopentadienyl)zirconium dimethyl,

[0066] bis(tetramethylcyclopentadienyl)zirconium dimethyl,

[0067] bis(ethyltetramethylcyclopentadienyl)zirconium dimethyl,

[0068] bis(indenyl)zirconium dimethyl,

[0069] bis(dimethylcyclopentadienyl)zirconium dihydride,

[0070] bis(trimethylcyclopentadienyl)zirconium dihydride,

[0071] bis(ethyltetramethylcyclopentadienyl)zirconium dihydride,

[0072] bis(trimethylsilylcyclopentadienyl)zirconium dimethyl,

[0073] bis(trimethylsilylcyclopentadienyl)zirconium dihydride,

[0074] bis(trifluoromethylcyclopentadienyl)zirconium dichloride,

[0075] bis(trifluoromethylcyclopentadienyl)zirconium dimethyl,

[0076] bis(trifluoromethylcyclopentadienyl)zirconium dihydride,

[0077] isopropylidenebis(indenyl)zirconium dichloride,

[0078] isopropylidenebis(indenyl)zirconium dimethyl,

[0079] isopropylidenebis(indenyl)zirconium dihydride,

[0080] pentamethylcyclopentadienyl(cyclopentadienyl)zirconiumdichloride,

[0081] pentamethylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,

[0082] pentamethylcyclopentadienyl(cyclopentadienyl)zirconium dihydride,

[0083] ethyltetramethylcyclopentadienyl(cyclopentadienyl)zirconiumdihydride,

[0084] isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride,

[0085] isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dimethyl,

[0086] dimethylsilyl(cyclopentadienyl)(fluorenyl)zirconium dimethyl,

[0087] isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dihydride,bis(cyclopentadienyl)zirconium dichloride,

[0088] bis(cyclopentadienyl)zirconium dimethyl,

[0089] bis(cyclopentadienyl)zirconium diethyl,

[0090] bis(cyclopentadienyl)zirconium dipropyl,

[0091] bis(cyclopentadienyl)zirconium diphenyl,

[0092] methylcyclopentadienyl(cyclopentadienyl)zirconium dichloride,

[0093] ethylcyclopentadienyl(cyclopentadienyl)zirconium dichloride,

[0094] methylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,

[0095] ethylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,

[0096] methylcyclopentadienyl(cyclopentadienyl)zirconium dihydride,

[0097] ethylcyclopentadienyl(cyclopentadienyl)zirconium dihydride,

[0098] dimethylcyclopentadienyl(cyclopentadienyl)zirconium dichloride,

[0099] trimethylcyclopentadienyl(cyclopentadienyl)zirconium dichloride,

[0100] tetramethylcyclopentadienyl(cyclopentadienyl)zirconiumdichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride,

[0101] tetramethylcyclopentadienyl(cyclopentadienyl)zirconiumdichloride, indenyl(cyclopentadienyl)zirconium dichloride,

[0102] dimethylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,

[0103] trimethylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,

[0104] tetramethylcyclopentadienyl(cyclopentadienyl)zirconium dimethyl,bis(pentamethylcyclopentadienyl)zirconium dimethyl,

[0105] ethyltetramethylcyclopentadienyl(cyclopentadienyl)zirconiumdimethyl, indenyl(cyclopentadienyl)zirconium dimethyl,

[0106] dimethylcyclopentadienyl(cyclopentadienyl)zirconium dihydride,

[0107] trimethylcyclopentadienyl(cyclopentadienyl)zirconium dihydride,bis(pentamethylcyclopentadienyl)zirconium dihydride,indenyl(cyclopentadienyl)zirconium dihydride,

[0108] trimethylsilylcyclopentadienyl(cyclopentadienyl)zirconiumdimethyl,

[0109] trimethylsilylcyclopentadienyl(cyclopentadienyl)zirconiumdihydride,

[0110] trifluoromethylcyclopentadienyl(cyclopentadienyl)zirconiumdichloride,

[0111] trifluoromethylcyclopentadienyl(cyclopentadienyl)zirconiumdimethyl,

[0112] trifluoromethylcyclopentadienyl(cyclopentadienyl)zirconiumdihydride,

[0113] bis(cyclopentadienyl)(trimethylsilyl)(methyl)zirconium,

[0114] bis(cyclopentadienyl)(triphenylsilyl)(methyl)zirconium,

[0115] bis(cyclopentadienyl)[tris(dimethylsilyl)silyl](methyl)zirconium,

[0116] bis(cyclopentadienyl)[(bis(methylsilyl)silyl](methyl)zirconium,

[0117]bis(cyclopentadienyl)(trimethylsilyl)(trimethylsilylmethyl)zirconium,

[0118] bis(cyclopentadienyl)(trimethylsilyl)(benzyl)zirconium,

[0119] methylenebis(cyclopentadienyl)zirconium dichoride,

[0120] ethylenebis(cyclopentadienyl)zirconium dichloride,

[0121] isopropylidenebis(cyclopentadienyl)zirconium dichloride,

[0122] dimethylsilylbis(cyclopentadienyl)zirconium dichloride,

[0123] methylenebis(cyclopentadienyl)zirconium dimethyl,

[0124] ethylenebis(cyclopentadienyl)zirconium dimethyl,

[0125] isopropylidenebis(cyclopentadienyl)zirconium dimethyl,

[0126] dimethylsilylbis(cyclopentadienyl)zirconium dimethyl,

[0127] methylenebis(cyclopentadienyl)zirconium dihydride,

[0128] ethylenebis(cyclopentadienyl)zirconium dihydride,

[0129] isopropylidenebis(cyclopentadienyl)zirconium dihydride,

[0130] dimethylsilylbis(cyclopentadienyl)zirconium dihydride,

[0131] bis(cyclopentadienyl)zirconiumbis(methanesulfonate),

[0132] bis(cyclopentadienyl)zirconiumbis(p-toluenesulfonate),

[0133] bis(cyclopentadienyl)zirconiumbis(trifluoromethanesulfonate),

[0134] bis(cyclopentadienyl)zirconiumtrifluoromethanesulfonate chloride,

[0135] bis(cyclopentadienyl)zirconiumbis(benzenesulfonate),

[0136] bis(cyclopentadienyl)zirconiumbis(pentafluorobenzenesulfonate),

[0137] bis(cyclopentadienyl)zirconiumbenzenesulfonate chloride,

[0138] bis(cyclopentadienyl)zirconium(ethoxy)trifluoromethanesulfonate,bis(tetramethylcyclopentadienyl)zirconiumbis(trifluoromethanesulfonate),

[0139] bis(indenyl)zirconiumbis(trifluoromethanesulfonate),

[0140] ethylenebis(indenyl)zirconiumbis(trifluoromethanesulfonate),isopropylidenebis(indenyl)zirconiumbis(trifluoromethanesulfonate),

[0141](t-butylamide)dimethyl(tetramethylcyclopentadienyl)silanedibenzylzirconium,(t-butylamide)dimethyl(2,3,4,5-tetramethylcyclopentadienyl)silanedibenzylzirconium,

[0142] indenylzirconiumtris(dimethylamide),

[0143] indenylzirconiumtris(diethylamide),

[0144] indenylzirconiumtris(di-n-propylamide),

[0145] cyclopentadienylzirconiumtris(dimethylamide),

[0146] methylcyclopentadienylzirconiumtris(dimethylamide),

[0147](t-butylamide)(tetramethylcyclopentadienyl)-1,2-ethanediylzirconiumdichloride,

[0148](methylamide)(tetramethylcyclopentadienyl)-1,2-ethanediylzirconiumdichloride,

[0149] (ethylamide)(tetramethylcyclopentadienyl)methylenezirconiumdichloride,(t-butylamide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdichloride,

[0150] (benzylamide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdichloride,

[0151](phenylphosphide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdibenzyl,

[0152] (phenylamide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdichloride,(2-methoxyphenylamide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdichloride,

[0153](4-fluorophenylamide)dimethyl(tetramethylcyclopentadienyl)silanezirconiumdichloride, and((2,6-di(1-methylethyl)phenyl)amide)dimethyl(tetramethylcyclopentadienyl)amidezirconiumdichloride.

[0154] Further, those corresponding to the formula (2) include abis(methylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(ethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(methylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(ethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(methylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(ethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(dimethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(trimethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(tetramethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(ethyltetramethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(indenyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(dimethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(trimethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(tetramethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(ethyltetramethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(indenyl)zirconium(methyl)(tetraphenylborate)tetrahydrofuran complex,abis(dimethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(trimethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(ethyltetramethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(trimethylsilylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(trimethylsilylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(trifluoromethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(trifluoromethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(indenyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(indenyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(indenyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, apentamethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anethyltetramethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, apentamethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anethyltetramethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, apentamethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anethyltetramethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidene(cyclopentadienyl)(fluorenyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidene(cyclopentadienyl)(fluorenyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidene(cyclopentadienyl)(fluorenyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(methyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(ethyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(propyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(phenyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, amethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(ethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, amethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, amethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, adimethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, atrimethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, atetramethylcyclopentadienyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, abis(pentamethylcyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anindenyl(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, adimethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, atrimethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, atetramethylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, abis(pentamethylcyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, acyclopentadienyl(indenyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, adimethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, atrimethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(pentamethylcyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anindenyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, atrimethylsilylcyclopentadienyl(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, atrimethylsilylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, atrifluoromethylcyclopentadienyl(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(trimethylsilyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(triphenylsilyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)[tris(trimethylsilyl)silyl]zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(trimethylsilylmethyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)(benzyl)zirconium(tetraphenylborate)tetrahydrofurancomplex, amethylenebis(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anethylenebis(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, adimethylsilylbis(cyclopentadienyl)zirconium(chloride)(tetraphenylborate)tetrahydrofurancomplex, amethylenebis(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anethylenebis(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, adimethylsilylbis(cyclopentadienyl)zirconium(methyl)(tetraphenylborate)tetrahydrofurancomplex, amethylenebis(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anethylenebis(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, anisopropylidenebis(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, adimethylsilylbis(cyclopentadienyl)zirconium(hydride)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(methanesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(p-toluenesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(trifluoromethanesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(benzenesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(cyclopentadienyl)zirconium(pentafluorobenzenesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(tetramethylcyclopentadienyl)zirconium(trifluoromethanesulfonate)(tetraphenylborate)tetrahydrofurancomplex, abis(indenyl)zirconium(trifluoromethanesulfonate)(tetraphenylborate)tetrahydrofurancomplex, anethylenebis(indenyl)zirconium(trifluoromethanesulfonate)(tetraphenylborate)tetrahydrofurancomplex, and anisopropylidenebis(indenyl)zirconium(trifluoromethanesulfonate)(tetraphenylborate)tetrahydrofurancomplex.

[0155] In the above examples, a di-substituted cyclopentadienyl ringincludes 1,2- and 1,3-substituted rings, and a tri-substitutedcyclopentadienyl ring includes 1,2,3- and 1,2,4-substituted rings.

[0156] Further, with respect to compounds of other metals of Groups 3,4, 5 and 6, such as titanium compounds and hafnium compounds, thoseequivalents to the above compounds may be mentioned. Further, a mixtureof such compounds may also be employed.

[0157] As the above component (B), (1) an ion exchanging layeredcompound or (2) an inorganic silicate having no layered structure i.e. anon-layered inorganic silicate, is used.

[0158] The ion exchanging layered compound is a compound having acrystal structure in which faces constituted by e.g. ionic bonds arepiled in parallel to one another by a weak bonding force, and thecontained ions are exchangeable. The majority of clays areion-exchanging layered compounds. Clays are generally composed of clayminerals as the main component. These clays, clay minerals andion-exchanging layered compounds may not only be natural products butalso be artificially synthesized products.

[0159] Examples of clays and clay minerals include an allophane groupsuch as allophane, a kaolin group such as dickite, nacrite, kaolinite oranauxite, a halloysite group such as metahalloysite or halloysite, aserpentine group such as chrysotile or antigorite, a smectite group suchas montmorillonite, beidellite, nontronite, saponite or hectorite, avermiculite mineral such as vermiculite, a mica mineral such as illite,sericite or glauconite, attapulgite, sepiolite, palygorskite, bentonite,Kibushi clay, gairome clay, hisingerite, pyrophyllite, chlorite, andother groups. The ion-exchanging layered compound used in the presentinvention may be a mixture of these minerals. Among these, particularlypreferred is a smectite group such as montmorillonite, beidellite,nontronite, saponite, hectorite, bentonite, teniorite or mica.

[0160] Further, examples of ion-exchanging layered compounds includeion-crystalline compounds having a layered crystal structure of e.g.hexagonal most densely packed type, antimony type, CdCl₂ type or CdI₂type. Specific examples of ion-exchanging layered compounds having sucha crystal structure include crystalline acidic salts of polyvalentmetals such as α-Zr(HAsO₄)₂.H₂O, α-Zr(HPO₄)₂, α-Zr(KPO₄)₂.3H₂O,α-Ti(HPO₄)₂, α-Ti(HAsO₄)₂.H₂O, α-Sn(HPO₄)₂.H₂O, γ-Zr(HPO₄)₂, γ-Ti(HPO₄)₂and γ-Ti(NH₄PO₄)₂.H₂O.

[0161] Examples of the non-layered inorganic silicate include zeoliteand diatomaceous earth.

[0162] Further, it is preferred that component (B) is subjected tochemical treatment. Here, the chemical treatment may be surfacetreatment for removing impurities attached on the surface, or treatmentwhich gives an influence to the crystal structure. Specifically,acid-treatment, alkali-treatment, salt-treatment and organicsubstance-treatment may, for example, be mentioned. By theacid-treatment, not only impurities on the surface will be removed, butalso the surface area will be increased, as cations such as Al, Fe andMg in the crystal structure will be eluted. By the alkali-treatment, thecrystal structure of clay will be destroyed, thus bringing about achange in the structure of clay. By the salt-treatment and the organicsubstance-treatment, it is possible to change the surface area or theinterlaminar distance by forming an ionic complex, a molecular complexor an organic derivative. Further, by replacing interlaminarexchangeable ions by another bulky ions by utilizing ionexchangeability, it is possible to obtain a layered substance having anenlarged interlaminar distance. Namely, bulky ions play a role ofsupporting the layered structure, and they are called pillars. Further,to introduce a separate substance between the layers of a layeredsubstance is called intercalation. The guest compound for intercalationmay, for example, be a cationic inorganic compound such as TiCl₄ orZrCl₄, a metal alcoholate such as Ti(OR)₄, Zr(OR)₄, PO(OR)₃ or B(OR)₃wherein R is alkyl or aryl, or a metal hydroxide ion such as[Al₁₃O₄(OH)₂₄]⁷⁺, [Zr₄(OH)₁₄]²⁺ or [Fe₃O(OCOCH₃)₅]⁺. These compounds maybe employed alone or in combination as a mixture of two or more of them.For intercalation of such a compound, a polymer obtained by hydrolyzinge.g. a metal alcoholate such as Si(OR)₄, Al(OR)₄ or Ge(OR)₄, or acolloidal inorganic compound such as SiO₂, may be present. Further, thepillar may, for example, be an oxide formed by heating for dehydrationafter intercalation of the above mentioned hydroxide ions betweenlayers.

[0163] Component (B) may be a single compound, or a mixture of two ormore of the above mentioned solid materials. Further, component (B) mayhave a wide rage of the average particle size. However, in the case ofgas phase polymerization or slurry polymerization, it is preferred toemploy spherical particles having an average particle size of at least 5μm. It is more preferred to employ spherical particles having an averageparticle size of at least 10 μm. It is most preferred to employspherical particles having an average particle size of from 10 to 100μm. Here, the average particle size is the one obtained by measurementin ethanol by means of a laser micronizer LMS-24, manufactured bySEISHIN K.K. Further, as component (B), a natural product or acommercial product may be used as it is, if it is in the form ofparticles. Otherwise, the shape of particles may be made, for example,in a spherical form, and the particle size may be controlled bygranulation, grading or fractionation.

[0164] Here, the granulation method may, for example, be agitationgranulation, spray granulation, tumbling granulation, briquetting,compacting, extrusion granulation, fluidized bed granulation, emulsiongranulation, submerged granulation or compression granulation. However,the granulation method is not particularly limited so long as it iscapable of granulating component (B). As a preferred granulation method,agitation granulation, spray granulation, tumbling granulation orfluidized bed granulation may be mentioned. Particularly preferred isagitation granulation or spray granulation. To carry out the spraygranulation, water or an organic solvent such as methanol, ethanol,chloroform, methylene chloride, pentane, hexane, heptane, toluene orxylene, may be used as a dispersing medium for the starting materialslurry. It is preferred to employ water as the dispersing medium. Theconcentration of component (B) in the starting material slurry for spraygranulation to obtain spherical particles, is usually from 0.1 to 70%,preferably from 1 to 50%, more preferably from 5 to 30%. The inlettemperature of hot air for spray granulation to obtain sphericalparticles varies depending upon the dispersing medium. When water isused as the dispersing medium, the inlet temperature is usually from 80to 260° C., preferably from 100 to 220° C.

[0165] Further, at the time of granulation, an organic substance, aninorganic salt or a binder may be employed. The useful binder may, forexample, be sugar, dextlose, corn syrup, gelatin, a glue, acarboxymethyl cellulose, a polyvinyl alcohol, water glass, magnesiumchloride, aluminum sulfate, aluminum chloride, magnesium sulfate, analcohol, glycol, starch, casein, latex, polyethylene glycol,polyethylene oxide, tar, pitch, alumina sol, silica gel, gum Arabic, orsodium alginate.

[0166] Preferred as component (B) is at least one compound selected fromthe group consisting of (1) ion exchanging layered compounds or (2)non-layered inorganic silicates, having a water content of at most 3 wt%, which is obtained by salt-treatment and/or acid-treatment. Such acompound can be obtained by subjecting at least one compound selectedfrom the group consisting of ion exchanging layered compounds ornon-layered inorganic silicates, to salt-treatment and/oracid-treatment. By the salt-treatment and/or the acid-treatment, it ispossible to change the acidity of the solid, as described above.

[0167] Further, it is preferred that at least 40%, preferably at least60%, of exchangeable Group 1 metal cations contained in said at leastone compound selected from the group consisting of ion exchanginglayered compounds or non-layered inorganic silicates, prior tosalt-treatment, are ion-exchanged by cations dissociated from theflowing salts.

[0168] Examples of the salts used in the salt-treatment to conduct theabove ion-exchanging, include a compound containing a cation of at leastone atom selected from the group consisting of Groups 2 to 14 atoms ofthe long-form Periodic Table, preferably a compound comprising a cationof at least one atom selected from the group consisting of Groups 2 to14 atoms and an anion of at least one member selected from a halogenatom, an inorganic acid and an organic acid, more preferably a compoundcomprising a cation of at least one atom selected from the groupconsisting of Groups 4 to 6 atoms and an anion of at least one memberselected from the group consisting of Cl, Br, I, F, PO₄, SO₄, NO₃, CO₃,C₂O₄, ClO₄, OOCCH₃, CH₃COCHCOCH₃, OCl₂, O(NO₃)₂, O(ClO₄)₂, O(SO₄), OH,O₂Cl₂, OCl₃, OOCH, OOCCH₂CH₃, C₂H₄O₄ and C₆H₅O₇.

[0169] More specific examples of the salts include CaCl₂, CaSO₄, CaC₂O₄,Ca(NO₃)₂, Ca₃(C₆H₅O₇)₂, MgCl₂, MgBr₂, MgSO₄, Mg(PO₄)₂, Mg(ClO₄)₂,MgC₂O₄, Mg(NO₃)₂, Mg(OOCCH₃)₂, MgC₄H₄O₄, Sc(OOCCH₃)₂, Sc₂(CO₃)₃,Sc₂(C₂O₄)₃, Sc(NO₃)₃, Sc₂(SO₄)₃, ScF₃, ScCl₃, ScBr₃, ScI₃, Y(OOCCH₃)₃,Y(CH₃COCHCOCH₃)₃, Y₂(CO₃)₃, Y₂(C₂O₄)₃, Y(NO₃)₃, Y(ClO₄)₃, YPO₄,Y₂(SO₄)₃, YF₃, YCl₃, La(OOCCH₃)₃, La(CH₃COCHCOCH₃)₃, La₂(CO₃)₃,La(NO₃)₃, La(ClO₄)₃, La₂(C₂O₄)₃, LaPO₄, La₂(SO₄)₃, LaF₃, LaCl₃, LaBr₃,LaI₃, Sm(OOCCH₃)₃, Sm(CH₃COCHCOCH₃)₃, Sm₂(CO₃)₃, Sm(NO₃)₃, Sm(ClO₄)₃,Sm₂(C₂O₄)₃, Sm₂(SO₄)₃, SmF₃, SmCl₃, SmI₃, YP(OOCCH₃)₃, Yb(NO₃)₃, Yb,(ClO₄)₃, Yb(C₂O₄)₃, Yb₂(SO₄)₃, YbF₃, YbCl₃, Ti(OOCCH₃)₄, Ti(CO₃)₂,Ti(NO₃)₄, Ti(SO₄)₂, TiF₄, TiCl₄, TiBr₄, TiI₄, Zr(OOCCH₃)₄, Zr(CH₃COCHCOCH₃)₄, Zr(CO₃)₂, Zr(NO₃)₄, Zr(SO₄)₂, ZrF₄, ZrCl₄, ZrBr₄, ZrI₄,ZrOCl₂, ZrO(NO₃)₂, ZrO(ClO₄)₂, ZrO(SO₄), Hf(OOCCH₃)₄, Hf(CO₃)₂,Hf(NO₃)₄, Hf(SO₄)₂, HfOCl₂, HfF₄, HfCl₄, HfBr₄, HfI₄, V(CH₃COCHCOCH₃)₃,VOSO₄, VOCl₃, VCl₃, VCl₄, VBr₃, Nb(CH₃COCHCOCH₃)₅, Nb₂(CO₃)₅, Nb(NO₃)₅,Nb₂(SO₄)₅, NbF₅, NbCl₅, NbBr₅, NbI₅, Ta(OOCCH₃)₅, Ta₂(CO₃)₅, Ta(NO₃)₅,Ta₂(SO₄)₅, TaF₅, TaCl₅, TaBr₅, TaI₅, Cr(CH₃COCHCOCH₃)₃, Cr(OOCH)₂OH,Cr(NO₃)₃, Cr(ClO₄)₃, CrPO₄, Cr₂(SO₄)₃, CrO₂Cl₂, CrF₃, CrCl₃, CrBr₃,CrI₃, MoOCl₄, MoCl₃, MoCl₄, MoCl₅, MoF₆, MoI₂, WCl₄, WCl₆, WF₆, WBr₅,Mn(OOCCH₃)₂, Mn(CH₃COCHCOCH₃)₂, MnCO₃, Mn(NO₃)₂, MnO, Mn(ClO₄)₂, MnF₂MnCl₂, MnBr₂, MnI₂, Fe(OOCCH₃)₂, Fe(CH₃COCHCOCH₃)₃, FeCO₃, Fe(NO₃)₃,Fe(ClO₄)₃, FePO₄, FeSO₄, Fe₂(SO₄)₃, FeF₃, FeCl₃, FeBr₃, FeI₂, FeC₆H₅O₇,Co(OOCCH₃)₂, Co(CH₃COCHCOCH₃)₃, CoCO₃, Co(NO₃)₂, CoC₂O₄, Co(ClO₄)₂,CO₃(PO₄)₂, CoSO₄, CoF₂, CoCl₂, CoBr₂, CoI₂, NiCO₃, Ni(NO₃)₂, NiC₂O₄,Ni(ClO₄)₂, NiSO₄, NiCl₂, NiBr₂, Pd(OOCCH₃)₂, Pd(NO₃)₂, PdSO₄, PdCl₂,PdBr₂, CuCl₂, CuBr₂, Cu(NO₃)₂, CuC₂O₄, Cu(ClO₄)₂, CuSO₄, Cu(OOCCH₃)₂,Zn(OOCCH₃)₂, Zn(CH₃COCHCOCH₃)₂, Zn(OOCH)₂, ZnCO₃, Zn(NO₃)₂, Zn(ClO₄)₂,Zn₃(PO₄)₂, Zn(SO₄), ZnF₂, ZnCl₂, ZnBr₂, ZnI₂, Cd(OOCCH₃)₂,Cd(CH₃COCHCOCH₃)₂, Cd(OOCCH₂CH₃)₂, Cd(NO₃)₂, Cd(ClO₄)₂, Cd(SO₄), CdF₂,CdCl₂, CdBr₂, CdI₂, AlCl₃, AlI₃, AlBr₃, AlF₃, Al₂(SO₄)₃, AlPO₄,Al₂(C₂O₄)₃, Al(NO₃)₃, Al(CH₃COCHCOCH)₃)₃, GeCl₄, GeBr₄, GeI₄,Sn(OOCCH₃)₄, Sn(SO₄)₂, SnF₄, SnCl₄, SnBr₄, SnI₄, Pb(OOCCH₃)₄, PbCO₃,PbHPO₄, Pb(NO₃)₂, Pb(ClO₄)₂, PbSO₄, PbF₂, PbCl₂, PbBr₂ and PbI₂.

[0170] The acid to be used for the acid-treatment is preferably selectedfrom hydrochloric acid, sulfuric acid, nitric acid, acetic acid andoxalic acid. Two or more salts and acids may be used for the salt andacid treatments, respectively. When the salt-treatment and theacid-treatment are conducted in combination, the salt-treatment may beconducted before or after the acid-treatment, or at the same time as theacid-treatment.

[0171] The treating conditions with the salts and the acids are notspecially limited, but they are appropriately selected among theconditions of a salt or acid concentration of from 0.1 to 30% by weight,a treating temperature of from room temperature to a boiling point and atreating time of from 5 minutes to 24 hours, so as to elute at least apart of the material constituting at least one compound selected fromthe group consisting of ion-exchanging layered compounds and non-layeredinorganic silicates. The salts and the acids are used generally inaqueous solutions.

[0172] Particle shapes may be controlled by pulverization or granulationbefore, during or after the above salt-treatment and/or acid-treatment.Further, chemical treatment such as alkali-treatment or organicsubstance-treatment may be conducted in combination. The component (B)thus obtained preferably has a pore volume of pores (having a radius ofat least 20 Å) of at least 0.1 cc/g, more preferably of from 0.3 to 5cc/g, as measured by a mercury injection method.

[0173] At least one compound selected from the group consisting of suchion-exchanging layered compounds and inorganic silicates usuallycontains adsorbed water and interlaminar water. It is preferred toremove these adsorbed water and interlaminar water by heat treatment sothat the water content of the compound will preferably be not higherthan 3% by weight.

[0174] Here, the “adsorbed water” is water adsorbed on the surface orbroken crystal face of particles of the ion-exchanging layered compoundor the non-layered inorganic silicate, and the “interlaminar water” iswater present between layers of crystal. The method for heat-treatmentto remove the adsorbed water and interlaminar water from theion-exchanging layered compound or the non-layered silicate is notparticularly limited, and various methods such as heat-dehydration,heat-dehydration under gas-flowing, heat-dehydration under reducedpressure and azeotropic dehydration with an organic solvent. The heatingtemperature is usually at least 100° C., preferably at least 150° C., soas to substantially remove interlaminar water, and it is not preferableto employ such a high temperature as to destroy the structure. Also,such a heat-dehydration method as to form a crosslinking structure, suchas heating in an air stream, is not preferable since the polymerizationactivity of the catalyst will thereby be lowered. The heating time is atleast 0.5 hour, preferably at least 1 hour. As mentioned above, thewater content is preferably not higher than 3% by weight, morepreferably not higher than 1% by weight, as measured on the basis of theassumption that the water content after dehydrating at 200° C. under apressure of 1 mmHg for 2 hours is 0% by weight. The lower limit ispreferably at least 0% by weight. It is necessary to handle thedehydrated component (B) having a water content of not higher than 3% byweight so as to maintain the water content at the same level when it iscontacted with the component (A) and optionally with the component (C).

[0175] Examples of an organic aluminum compound optionally used as thecomponent (C) include a compound of the formula:

AlR⁸ _(j)X_(3-j)

[0176] (wherein R⁸ is a C₁₋₂₀ hydrocarbon group, X is hydrogen, halogenor an alkoxy (C₁₋₁₀) group, and j is a number of 0<j≦3), e.g. atrialkylaluminum such as trimethylaluminum, triethylaluminum,tripropylaluminum or triisobutylaluminum, and a halogen- oralkoxy-containing alkylaluminum such as diethylaluminum monochloride ordiethylaluminum methoxide. In addition to these compounds, analuminoxane such as methylaluminoxane can also be used. Among thesecompounds, a trialkylaluminum is particularly preferred.

[0177] A catalyst is preferably prepared by preliminarily contactingethylene to the component (A) and the component (B), and optionally thecomponent (C). The contacting order of the respective components of thecatalyst is not particularly limited. They may, for example, becontacted in the following orders:

[0178] {circle over (1)} Components (A) and (B) are contacted.

[0179] {circle over (2)} Components (A) and (B) are contacted, and thencomponent (C) is added.

[0180] {circle over (3)} Components (A) and (C) are contacted, and thencomponent (B) is added.

[0181] {circle over (4)} Components (B) and (C) are contacted, and thencomponent (A) is added.

[0182] Otherwise, the three components may simultaneously be contacted.

[0183] During or after contacting the respective catalyst components, apolymer such as polyethylene or polypropylene, or a solid of aninorganic oxide such as silica or alumina, may be present or contacted.

[0184] The contacting may be conducted in an inert gas such as nitrogenor in an inert hydrocarbon solvent such as pentane, hexane, heptane,toluene and xylene. The contacting temperature is from −20° C. to aboiling point of a solvent, preferably from room temperature to aboiling point of a solvent.

[0185] With regard to the amounts of the respective catalyst components,the amount of the component (A) is from 0.0001 to 10 mmol, preferablyfrom 0.001 to 5 mmol, per g of the component (B) and the amount of thecomponent (C) is from 0.01 to 10000 mmol, preferably from 0.1 to 100mmol, per g of the component (B). Also, the atomic ratio of a transitionmetal in the component (A)/aluminum in the component (C) is 1/0.01 to1000000, preferably 1/0.1 to 100000.

[0186] The preliminary polymerization with ethylene is preferablycarried out by supplying etylene under contact of the above respectivecomponents in an inert solvent, so as to produce from 0.01 to 1000 g,preferably from 0.1 to 100 g, of a polymer per g of the solid catalyst.The preliminary polymerization temperature is usually from −50 to 100°C., preferably from 0 to 100° C., and the preliminary polymerizationtime is usually from 0.1 to 100 hours, preferably from 0.1 to 20 hours.

[0187] The solid catalyst thus obtained may be used for thepolymerization reaction as it is without washing, or may be used afterwashing. In a case where the treatment is carried out in a solvent suchas an inert hydrocarbon, the resulting slurry may be used as it is, orthe solvent may be distilled off to use the catalyst in a powder form.

[0188] The above described catalyst may be used, if necessary, incombination with an organic aluminum compound, to produce the copolymerof the present invention. The organic aluminum compound to be used here,may be the same compound as the above described component (C). Theamount of the organic aluminum compound to be used here, is selected sothat the molar ratio of aluminum in the organic aluminum compound to thetransition metal in the catalyst component (A) will be from 1:0 to1:10000.

[0189] The ethylene-α-olefin copolymer of the present invention isobtained by copolymerizing ethylene with a C₃₋₂₀, preferably C₃₋₈,linear α-olefin such as propylene, 1-butene, 1-hexene, 1-octene,1-decene, 3-methylbutene-1 or 4-methylpentene-1. Although notparticularly limited, the proportion of the α-olefin is preferably from0.5 to 20%, whereby the above conditions (a) to (c) of the presentinvention can readily be satisfied.

[0190] The polymerization reaction is conducted in the presence orabsence of a solvent such as a liquefied α-olefin or an inerthydrocarbon such as butane, pentane, hexane, heptane, toluene orcyclohexane. The temperature is usually within a range of from −50° C.to +250° C. The pressure is not particularly limited, but is preferablywithin a range of from atmospheric pressure to about 2,000 kgf/cm².Further, hydrogen as a molecular weight controlling agent may be presentin the polymerization system.

[0191] Now, the present invention will be described in further detailwith reference to Examples. However, it should be understood that thepresent invention is by no means restricted by such specific Examples.

[0192] All of the following catalyst preparation steps andpolymerization steps were conducted under an atmosphere of purifiednitrogen. Further, the solvent used was one dehydrated and purified bymeans of molecular sieve 4A.

EXAMPLE A-1

[0193] (1) Chemical Treatment of Clay Mineral

[0194] 1 kg of synthetic mica (ME-100, manufactured by Corp ChemicalCo., Ltd.) was dispersed in 3.2 kg of desalinated water having 0.2 kg ofzinc sulfate dissolved therein, and stirred at room temperature for onehour, followed by filtration. After washing with desalinated water, thesolid content was adjusted to a concentration of 25%, and the slurrythus obtained was introduced into a spray drier to obtain sphericalgranulated particles. The particles were further dried under reducedpressure at 200° C. for two hours.

[0195] (2) Preparation of Catalyst

[0196] Into a reactor having a capacity of 10 l and equipped with aninduction stirrer, 4.4 l of n-heptane and 150 g of the particles of thesynthetic mica obtained in the above step (1), were introduced. Asolution having 12.0 mmol ofdimethylsilylenebis(4,5,6,7-tetrahydroindenyl) zirconium dichloridedissolved in 600 ml of toluene, was added thereto, followed by stirringat room temperature for 10 minutes.

[0197] (3) Preliminary Polymerization

[0198] To the above stirred mixture, 71.5 mmol of triethylaluminum wasthen added, and the temperature of the system was adjusted to 60° C. Tenminutes later, ethylene gas was introduced, and the reaction wascontinued for two hours. Polyethylene formed during this period was 549g.

[0199] (4) Copolymerization of ethylene-1-butene (Slurry Polymerization)

[0200] Into a 3 l of autoclave, 1.5 l of n-heptane, 2.5 mmol oftriethylaluminum and 100 ml of 1-butene were introduced, and thetemperature was raised to 65° C. Then, the preliminarily polymerizedcatalyst obtained in step (3), was introduced in an amount of 100 mg asthe mica component, together with ethylene, and while supplying a gasmixture of ethylene and 1-butene (1-butene/ethylene=7.0 wt %) dependingupon the consumption of ethylene, polymerization was carried out at 65°C. for two hours while maintaining the total pressure at a level of 22kg/cm²G. After the two hours, ethanol was added to terminate thepolymerization. The obtained ethylene-1-butene copolymer was 228 g. Thebasic physical properties of the obtained polymer and the results of thecross fractionation measurement are shown in Table 1.

[0201] (5) Film Extrusion

[0202] The obtained ethylene-1-butene copolymer was subjected toblown-film extrusion to obtain a film having a thickness of 30 μm. Theextrusion was carried out by means of a 20 mmφ twin screw extruder at atemperature of 180° C. with a die of 25 mm in diameter with a lip widthof 3 mm, with an extruded amount of 18 g at a blow-up ratio of 2.0. Theobtained film had a haze of 3.1% and thus had high transparencycorresponding to the density.

[0203] The haze was measured in accordance with JIS K-7105.

EXAMPLE A-2

[0204] Gas phase polymerization was carried out by using thepreliminarily polymerized catalyst obtained in Example A-1 (3). Namely,446 mg/hr of the above solid catalyst and 1700 mg/hr of triethylaluminumwere intermittently supplied to a continuous system gas phasepolymerization reactor wherein a gas mixture of ethylene and 1-butene(1-butene/ethylene=3.0%) was circulated. The polymerization reactionconditions were 88° C., a pressure of 20 kg/cm²G and an averageresidence time of 6.9 hours, and the average polymerization rate offormed polyethylene was 8.7 kg/hr. The basic physical properties of theobtained polymer, the results of the cross fractionation measurement andthe haze of the film are shown in Table 1.

EXAMPLE A-3

[0205] (1) Chemical Treatment of Clay Mineral

[0206] 22.6 kg of commercially available montmorillonite (Kunipia Fmanufactured by Kunimine Kogyo K.K.) was dissolved in an acidic aqueoussolution having 15 kg of 35% hydrochloric acid added to 6.3 l ofdesalinated water, and stirred at 90° C. for two hours. This solidcomponent was washed with desalinated water, and then this aqueousslurry of montmorillonite was adjusted to a solid content concentrationof 10%, followed by spray granulation by means of a spray drier toobtain spherical particles.

[0207] (2) Preparation of Catalyst

[0208] Into a reactor having a capacity of 10 l and equipped with aninduction stirrer, 625 ml of toluene and 10 g of the particles ofmontmorillonite obtained in the above step (1) were introduced. Whilemaintaining the temperature at 25° C., a mixed solution comprising 450mmol of triethylaluminum and 343 ml of toluene was added thereto in itsentire amount, followed by stirring for one hour. The supernatant waswithdrawn, and the remaining solid component was washed with toluene.Then, n-heptane was added thereto to bring the total amount to 4.4 l.Then, a solution having 12.0 mmol ofdimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloridedissolved in 600 ml of toluene, was added thereto at 25° C., followed bystirring for 60 minutes.

[0209] (3) Preliminary Polymerization

[0210] To the above stirred mixture, 33.0 mmol of triethylaluminum wasthen added, and the temperature of the system was adjusted to 80° C. Tenminutes later, ethylene gas was introduced, and the reaction wascontinued for 2.5 hours. Polyethylene formed during this period was 365g.

[0211] (4) Ethylene-1-butene Copolymer and Film Extrusion

[0212] Ethylene-1-butene gas phase polymerization and film extrusionwere carried out in the same manner as in Example A-2 except that thepreliminarily polymerized catalyst obtained in the above step (3) wasused. However, 1340 mg/hr of the solid catalyst and the 860 mg/hr oftriethylaluminum were intermittently supplied. The polymerizationreaction conditions were 88° C., a pressure of 20 kg/cm²G and an averageresidence time of 7.0 hours, and the average polymerization rate offormed polyethylene was 8.6 kg/hr. The basic physical properties of theobtained polymer, the results of the cross fractionation measurement andthe phase of the film are shown in Table 1.

EXAMPLE A-4

[0213] (1) Chemical Treatment of Clay Mineral

[0214] 1 kg of synthetic mica (ME-100, manufactured by Corp ChemicalCo., Ltd.) was dissolved in 3.4 kg of desalinated water having 0.80 kgof chromium (III) nitrate dissolved therein, and stirred at roomtemperature for two hours, followed by filtration. After washing withdesalinated water, the solid content was adjusted to a concentration of25%, and the slurry thus obtained was introduced into a spray drier toobtain spherical granulated particles. The particles were further driedunder reduced pressure at 200° C. for two hours.

[0215] (2) Preparation of Catalyst

[0216] Into a reactor having a capacity of 10 l and equipped with aninduction stirrer, 4.4 l of n-heptane and 150 g of the particles ofsynthetic mica obtained in the above step (1), were introduced. Then, asolution having 12.0 mmol of bis(n-butylcyclopentadienyl)zirconiumdichloride dissolved in 600 ml of toluene, was added thereto, followedby stirring at room temperature for 10 minutes.

[0217] (3) Preliminary Polymerization

[0218] To the above stirred mixture, 71.5 mmol of triethylaluminum wasthen added, and the temperature of the system was adjusted to 60° C. Tenminutes later, ethylene gas was introduced, and the reaction wascontinued for two hours. Polyethylene formed during this period was 592g.

[0219] (4) Ethylene-1-butene Copolymer and Film Extrusion

[0220] Ethylene-1-butene gas phase polymerization and film extrusionwere carried out in the same manner as in Example A-2 except that thepreliminarily polymerized catalyst obtained in the above step (3) wasused. Namely, 363 mg/hr of the solid catalyst and 568 mg/hr oftriethylaluminum were intermittently supplied to a continuous system gasphase polymerization reactor in which a gas mixture of ethylene and1-butene (1-butene/ethylene=6.4%) was circulated. The polymerizationreaction conditions were 83° C., a pressure of 20 kg/cm²G and an averageresidence time of 14 hours, and the average polymerization rate offormed polyethylene was 4.3 kg/hr. The basic physical properties of theobtained polymer, the results of the cross fractionation measurement andthe haze of the film are shown in Table 1.

EXAMPLE A-5

[0221] (1) Preparation of Catalyst and Preliminary Polymerization

[0222] Into a reactor having a capacity of 1.5 l and equipped with aninduction stirrer, 800 ml of n-heptane and 24 g of the particles ofsynthetic mica obtained in Example A-4(l) were introduced. A solutionhaving 1.92 mmol of bis(n-butylcyclopentadienyl)zirconium dichloridedissolved in 96 ml of toluene, was added thereto, followed by stirringat room temperature for 10 minutes. Then, 11.5 mmol of triethylaluminumwas added thereto, and the temperature of the system was adjusted to 60°C. Ten minutes later, ethylene gas was introduced, and the reaction wascontinued for two hours. Polyethylene formed during this period was 54.7g.

[0223] (2) Ethylene-1-butene Copolymer and Film Extrusion

[0224] Slurry polymerization was carried out by using the preliminarilypolymerized catalyst obtained in step (1). Namely, into a 3 l autoclave,1.5 l of n-heptane, 2.5 mmol of triethylaluminum and 200 ml of 1-butenewere added, and the temperature was raised to 65° C. Then, the abovecatalyst was introduced in an amount of 100 mg as the mica componenttogether with ethylene, and polymerization was carried out at 65° C. fortwo hours while maintaining the total pressure at a level of 22 kg/cm²G.Two hours later, ethanol was added to terminate the polymerization. Theobtained ethylene-1-butene copolymer was 285 g. The basic physicalproperties of the obtained polymer, the results of the crossfractionation measurement and the haze of the film are shown in Table 1.

EXAMPLE A-6

[0225] The operation was carried out in the same manner as in ExampleA-5(l) and (2) except that bis(n-butylcyclopentadienyl)zirconiumdichloride was changed to biscyclopentadienyl zirconium dichloride.Polyethylene formed during the preliminary polymerization was 91.7 g.The copolymer obtained by the ethylene-1-butene copolymerization was 230g. The basic physical properties of the obtained polymer, the results ofthe cross fractionation measurement and the haze of the film are shownin Table 1.

EXAMPLE A-7

[0226] The preliminarily polymerized catalyst was produced in the samemanner as in Example A-5(1) except thatbis(n-butylcyclopentadienyl)zirconium dichloride was changed todimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, andethylene-1-butene copolymerization and film extrusion were carried outin the same manner as in Example A-1(4) and (5). Polyethylene formedduring the preliminary polymerization was 93.6 g. The copolymer obtainedby the ethylene-1-butene copolymerization was 298 g. The basic physicalproperties of the obtained polymer, the results of the crossfractionation measurement and the haze of the film are shown in Table 1.

COMPARATIVE EXAMPLE A-1

[0227] EXACT3030 manufactured by Exxon Chemical Co., Ltd., which is acommercially available polymer product obtained by a metallocenecatalyst, was subjected to film extrusion under the same condition as inExample A-1(5). The haze of the film was 5.5 and thus had lowtransparency corresponding to the density. The basic physical propertiesof the product and the results of the cross fractionation measurementare shown in Table 1.

COMPARATIVE EXAMPLE A-2

[0228] Affinity FM1570 manufactured by Dow Chemical Co., Ltd., which isa commercially available polymer product produced by a metallocenecatalyst, was subjected to film extrusion under the same condition as inExample A-1(5). The film had a haze of 7.0 and thus had low transparencycorresponding to the density. The basic physical properties of theproduct and the result of the cross fractionation measurement are shownin Table 1.

COMPARATIVE EXAMPLE A-3

[0229] UF240 manufactured by Mitsubishi Chemical Co., Ltd., which is acommercially available polymer product produced by a Zieglar catalyst,was subjected to film extrusion under the same condition as in ExampleA-1(5). The film had a haze of 20.1 and thus had very low transparencycorresponding to the density. The basic physical properties of theproduct and the results of the cross fractionation measurement are shownin Table 1. TABLE 1 Characteristics of copolymer Condition (b) Condition(c) Condition (d) Condition (a) Claimed Claimed Claimed Claimed ClaimedEvaluation Density MFR formula Tmax W₆₀ W₉₀ formula formula formulaformula Haze (g/cm³) MT (g/10 min) (1) (° C.) (wt %) (wt %) (2) (3) (4)(5) (%) Example A-1 0.9180 1.33 1.82 ◯ 73.0 0.3 1.6 ◯ ◯ ◯ ◯ 3.1 ExampleA-2 0.9180 0.74 1.90 ◯ 74.2 3.3 1.8 ◯ ◯ ◯ ◯ 5.0 Example A-3 0.9210 1.072.03 ◯ 74.4 1.9 5.4 ◯ ◯ ◯ ◯ 3.3 Example A-4 0.9200 2.17 1.09 ◯ 77.1 0.24 4.2 ◯ ◯ ◯ ◯ 3.5 Example A-5 0.9236 1.65 4.69 ◯ 75.5 0.3 5.8 ◯ ◯ ◯◯ 5.1 Example A-6 0.9211 4.25 1.73 ◯ 73.9 1.8 3.0 ◯ ◯ ◯ ◯ 3.0 ExampleA-7 0.9233 4.26 1.42 ◯ 74.4 2.7 6.9 ◯ ◯ ◯ ◯ 3.0 Comparative 0.9100 0.272.13 X 68.8 14   0   ◯ ◯ X X 5.5 Example A-1 Comparative 0.9160 2.831.04 ◯ 76.6 5.6 0   ◯ X X X 8.0 Example A-2 Comparative 0.9200 0.76 1.95◯ 91.8 24.1  15.6 X X ◯ X 20.1  Example A-3

[0230] In the above Table, symbol ◯ means that the formula concerned wassatisfied, and symbol × means that the formula concerned was notsatisfied.

[0231] The following catalyst preparation steps and polymerization stepswere all carried out in a purified nitrogen atmosphere. Further, thesolvent used was one dehydrated and purified by means of molecular sieve13X.

EXAMPLE B-1

[0232] (1) Chemical Treatment of Clay Mineral

[0233] 1 kg of synthetic mica (ME-100, manufactured by Corp ChemicalCo., Ltd.) was dispersed in 3.4 kg of desalinated water having 0.60 kgof chromium (III) nitrate dissolved therein, and stirred at 50° C. forone hour, followed by filtration. After washing with desalinated water,the solid component was adjusted to a concentration of 20%, and theslurry thus obtained was subjected to spray granulation to obtainspherical particles. The particles were further dried under reducedpressure at 200° C. for two hours.

[0234] (2) Preparation of Catalyst

[0235] Into a reactor having a capacity of 10 l and equipped with aninduction stirrer, 5.4 l of n-heptane and 50 g of the particles ofsynthetic mica obtained in the above step (1), were introduced. Then, asolution having 4.0 mmol of bis(n-butylcyclopentadienyl)zirconiumdichloride dissolved in 600 ml of toluene, was added thereto, followedby stirring at room temperature for 10 minutes.

[0236] (3) Preliminary Polymerization

[0237] To the above stirred mixture, 23.6 mmol of triethylaluminum wasthen added, and the temperature of the system was adjusted to 60° C. Tenminutes later, ethylene gas was introduced, and the reaction wascontinued for 3 hours. Polyethylene formed during this period was 819 g.

[0238] (4) Ethylene-1-butene Copolymerization (Gas Phase Polymerization)

[0239] 233 mg/hr of the above solid catalyst and 510 mg/hr oftriethylaluminum were intermittently supplied to a continuous system gasphase polymerization reactor in which a gas mixture of ethylene and1-butene (1-butene/ethylene=4.4 mol %) was circulated. Thepolymerization reaction conditions were 83° C., an ethylene pressure of18 kg/cm²G and an average residence time of 10.7 hours, and the averagepolymerization rate of formed polyethylene was 5.6 kg/hr. The basicphysical properties of the obtained polymer, the results of the crossfractionation measurement and the haze of the film are shown in Table 2.

[0240] (5) Film Extrusion

[0241] The obtained ethylene-1-butene copolymer was subjected toblown-film extrusion to obtain a film having a thickness of 30 μm. Theextrusion was carried out by means of a 40 mmφ single screw extruder ata temperature of 180° C. by a die of 75 mm in diameter, with a lip widthof 3 mm with an extruded amount of 14 kg at a blow-up ratio of 2.0. Theobtained film had a haze of 4.6% and thus had high transparencycorresponding to the density.

[0242] The haze was measured in accordance with JIS K-7105, and the melttension (MT) was measured by means of a capilograph manufactured byKabushiki Kaisha Toyo Seiki Seisakusho under such conditions that thenozzle diameter was 2.095 mm, the nozzle length was 8 mm, the flow-inangle was 180°, the temperature was 190° C., the extrusion rate was 1.0cm/min, the withdrawing rate was 4.0 m/min, and the distance from thedie outlet to the lower end of the V-pully of the tension detector was40 cm.

EXAMPLE B-2

[0243] (1) Ethylene-1-butene Copolymerization

[0244] Slurry polymerization was carried out by using the preliminarilypolymerized catalyst obtained in Example B-1(3). Namely, into a 3 lautoclave, 1.5 l of n-heptane, 2.5 mmol of triethylaluminum and 200 mlof 1-butene were introduced, and the temperature was raised to 65° C.Then, the above preliminarily polymerized catalyst was introduced in anamount of 100 mg as the mica component together with ethylene, andpolymerization was carried out at 65° C. for two hours while maintainingthe total pressure at a level of 22 kg/cm²G. After the two hours,ethanol was added to terminate the polymerization. The obtainedethylene-1-butene copolymer was 263 g. The basic physical properties ofthe obtained polymer are shown in Table 2.

[0245] (2) Film Extrusion

[0246] The obtained ethylene-1-butene copolymer was subjected toblown-film extrusion to obtain a film having a thickness of 30 μm. Theextrusion was carried out by means of a 20 mmφ twin screw extruder at atemperature of 180° C. with a die of 25 mm in diameter with a lip widthof 3 mm with an extrusion amount of 18 g at a blow-up ratio of 2.0. Theobtained film had a haze of 5.1% and thus had high transparencycorresponding to the density.

COMPARATIVE EXAMPLE B-2

[0247] LF240 manufactured by Mitsubishi Chemical Co., Ltd., which is acommercially available high pressure method low density polyethylene,was subjected to blown-film extrusion under the same conditions as inExample B-1(5). The film had a haze of 8.0% and thus had lowtransparency corresponding to the density. The basic physical propertiesof the product are shown in Table 2.

COMPARATIVE EXAMPLE B-3

[0248] UE320 manufactured by Mitsubishi Chemical Co., Ltd., which is acommercially available polymer product produced by a chromium typecatalyst, was subjected to blown-film extrusion under the sameconditions as in Example B-1(5). The film had a haze of 20% and thus hadvery low transparency corresponding to the density. The basic physicalproperties of the product are shown in Table 2.

COMPARATIVE EXAMPLE B-1

[0249] Affinity PL1840 manufactured by Dow Chemical Co., Ltd., which isa commercially available polymer product produced by a metallocenecatalyst, was subjected to film extrusion under the same conditions asin Example B-1(5). The film had a haze of 6.2% and thus had lowtransparency corresponding to the density. The basic physical propertiesof the product are shown in Table 2. TABLE 2 Characteristics ofcopolymer Condition (b) Condition (c) Condition (d) Condition (a)Claimed Claimed Claimed Claimed Claimed Evaluation Density MFR formulaTmax W₆₀ W₉₀ formula formula formula formula Haze (g/cm³) MT (g/10 min)(1) (° C.) (wt %) (wt %) (2) (3) (4) (5) (%) Example B-1 0.9303  1.761.29 ◯ 83.2 0    22.5 ◯ ◯ ◯ ◯ 6.2 Example B-2 0.9210  2.59 1.20 ◯ 73.30.7   5.0 ◯ ◯ ◯ ◯ 4.5 Comparative 0.9110  3.28 1.05 ◯ 71.5 9.7 0 ◯ ◯ X X6.2 Example B-1 Comparative 0.9224 10.8  0.72 ◯ 76.9 8.8 0 ◯ X X ◯ 8.0Example B-2 Comparative 0.9250 5.9 0.89 ◯ 76.7 20.7    4.5 ◯ X X X 32  Example B-3

[0250] The ethylene-α-olefin copolymer of the present invention has ahigh melt tension and is excellent in a film extrusion property, wherebyit is possible to produce a film excellent in transparency, gloss anddrape.

What is claimed is:
 1. An ethylene-α-olefin copolymer which is acopolymer of ethylene with a C₃₋₂₀ α-olefin and which satisfies thefollowing conditions (a) to (c): (a) the density (D) is from 0.850 to0.950 g/cm³, (b) the relation between the melt tension (MT) and the meltflow rate (MFR) at 190° C. satisfies the following formula (1):log(MT)≧−0.91×log(MFR)+0.06   (1), and (c) the following three formulae(2), (3) and (4) are satisfied: Tmax≦972D−813   (2) logW₆₀≦−0.114Tmax+9.48   (3) logW₉₀≧0.0394 Tmax−2.95   (4) where D is the density,Tmax is the elution peak temperature (° C.) by the cross fractionationmeasurement, W₆₀ is the weight ratio (wt %) of a soluble content at 60°C. or lower, and W₉₀ is the weight ratio (wt %) of a soluble content at90° C. or higher.
 2. The ethylene-α-olefin copolymer according to claim1, wherein said condition (c) is such that the following three formulae(2)′, (3) and (4)′ are satisfied: Tmax≦972D−816   (2)′logW₆₀≦−0.114Tmax+9.48   (3) logW₉₀≧0.0394 Tmax−2.81   (4)′
 3. The ethylene-α-olefincopolymer according to claim 1, wherein the density of said condition(a) is from 0.850 to 0.935 g/cm³.
 4. The ethylene-α-olefin copolymeraccording to claim 1, which satisfies the following condition (d) inaddition to said conditions (a) to (c): (d) the film haze(%)≦1.5×10⁴×(D−0.9)²+3   (5)